ok. That's better! Now here's my 2 cents...
To me it sounds like you can get a deal on a SF M3. Regular retail for a brand new M3 is $252 USD. So if you can get it for less (i think you said $180) then that's a pretty good deal - to me at least - especially if it's brand new.
You wanted 100+ lumens. The M3 will deliver.
You said runtime is not that big an issue. So just make sure you keep spare 123s handy, in multiples of 3 of course. /ubbthreads/images/graemlins/smile.gif
You also said you'd be using the M3 with 5-10 second bursts. SF advertises that 3 cells should last approx upto 60 minutes of continuous runtime. Most of us here would then say that the actual time would be less since by the end of the 60 minutes the output would be severely diminished. Out comes the new batteries. /ubbthreads/images/graemlins/grin.gif
For carrying, I prefer holsters on a duty belt or regular belt. I like nylon. SF of course, sells a special polymer holster for the M3. I'm sure you are already aware of that. It's on their website. The M3 is a very uniquely shaped light so finding an aftermarket holster may be challenging. But maybe someone else can give you better leads for this.
Streamlight (not streamline) makes great lights IMO. But I agree that their overall quality is not identical fo SF's. But their products generally cost less. A light to compare to the SF M3 is perhaps the SL TL3.
Rechargeable vs disposable. For regular duty use I prefer rechargeable. My duty light gets lots of regular use (day and night) so going rechargeable is more cost effective for me. My duty light (I'm in security) is the SF L7. I keep it charged and keep a charged spare batt available as well. For most close and medium range lighting needs the L7 does me proud.
Last point: Size & output. The M3 *is* on the longer/larger end of the scale. And I agree its size doesnt allow it to be the best for off-duty concealed carry. I prefer any of the SF E series for plain clothes use. But you wont get the output of the M3 then. You will have to decide what is important to you right now. Another quick point to make is there are times you dont NEED the output of an M3. Say you only need light for something up close. The M3 would be overkill! So if you still use the M3 EVERYtime you need a little or a lot of light, then you will find your batteries dont last too long afterall. That's why some people carry multiple lights, or a light that has multiple output levels.
I say, get the M3 or the C3 (I have the C3 and I love it) ! Both are durable, bright, & dependable. Use either for when you really need to punch holes in the dark. For other times that are less "critical" maybe get another lower output light that will give you longer runtime. Many LED lights would suffice. I like the Inova X5T. Not too expensive and built like a tank! There are plenty of other LED lights to choose from.
Hope this helped a little. /ubbthreads/images/graemlins/smile.gif
Either way you go, good luck!
Be safe,
CQB
ps. With all its advertised features, The Gladius is a one of a kind of lighting tool. I cant think of another brand / model that would be a fair comparison. Definitely high end. Definitely one I cannot afford. Definitely one that I *will* end up buying anyways. /ubbthreads/images/graemlins/crazy.gif /ubbthreads/images/graemlins/broke.gif /ubbthreads/images/graemlins/crazy.gif